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Study Guide and Review State whether each sentence is true or false. If false, replace the underlined word or phrase to make a true sentence. 1. The arithmetic mean of two numbers is the positive square root of the product of the numbers. SOLUTION: false, geometric ANSWER: false, geometric 2. Extended ratios can be used to compare three or more quantities. SOLUTION: true ANSWER: true 3. To find the length of the hypotenuse of a right triangle, take the square root of the difference of the squares of the legs. SOLUTION: false, sum ANSWER: false, sum 4. An angle of elevation is the angle formed by a horizontal line and an observer’s line of sight to an object below the horizon. SOLUTION: false, depression ANSWER: false, depression 5. The sum of two vectors is the resultant. SOLUTION: true ANSWER: true 6. Magnitude is the angle a vector makes with the x-axis. SOLUTION: false, length of the vector ANSWER: false, length of the vector 7. A vector is in standard position when the initial point is at the origin. SOLUTION: true Manual - Powered by Cognero eSolutions ANSWER: true Page 1 SOLUTION: false, length of the vector ANSWER: Study Guide and Review false, length of the vector 7. A vector is in standard position when the initial point is at the origin. SOLUTION: true ANSWER: true 8. The component form of a vector describes the vector in terms of change in x and change in y. SOLUTION: true ANSWER: true 9. The Law of Sines can be used to fi nd an angle measure when given three side lengths. SOLUTION: false, Law of Cosines ANSWER: false, Law of Cosines 10. A trigonometric ratio is a ratio of the lengths of two sides of a right triangle. SOLUTION: true ANSWER: true Find the geometric mean between each pair of numbers. 11. 9 and 4 SOLUTION: By definition, the geometric mean x of any two numbers a and b is given by Therefore, the geometric mean of 9 and 4 is ANSWER: 6 12. and SOLUTION: By definition, the geometric mean x of any two numbers a and b is given by Therefore, the geometric mean of and is ANSWER: eSolutions Manual - Powered by Cognero 13. and Page 2 ANSWER: Study 6 Guide and Review 12. and SOLUTION: By definition, the geometric mean x of any two numbers a and b is given by Therefore, the geometric mean of and is ANSWER: 13. and SOLUTION: By definition, the geometric mean x of any two numbers a and b is given by Therefore, the geometric mean of and is ANSWER: 14. Find x, y, and z. SOLUTION: By the Geometric Mean (Leg) Theorem the altitude drawn to the hypotenuse of a right triangle separates the hypotenuse into two segments. The length of a leg of this triangle is the geometric mean between the length of the hypotenuse and the segment of the hypotenuse adjacent to that leg. Set up a proportion and solve for y and x: Manual - Powered by Cognero eSolutions Page 3 ANSWER: Study Guide and Review 14. Find x, y, and z. SOLUTION: By the Geometric Mean (Leg) Theorem the altitude drawn to the hypotenuse of a right triangle separates the hypotenuse into two segments. The length of a leg of this triangle is the geometric mean between the length of the hypotenuse and the segment of the hypotenuse adjacent to that leg. Set up a proportion and solve for y and x: and By the Geometric Mean (Altitude) Theorem the altitude drawn to the hypotenuse of a right triangle separates the hypotenuse into two segments. The length of this altitude is the geometric mean between the lengths of these two segments. Solve for z ANSWER: 15. DANCES Mike is hanging a string of lights on his barn for a square dance. Using a book to sight the top and bottom of the barn,- Powered he can see he is 15 feet from the barn. If his eye level is 5 feet from the ground, how tall is the barn?Page 4 eSolutions Manual by Cognero SOLUTION: Draw a rough figure for the given information. ANSWER: Study Guide and Review 15. DANCES Mike is hanging a string of lights on his barn for a square dance. Using a book to sight the top and bottom of the barn, he can see he is 15 feet from the barn. If his eye level is 5 feet from the ground, how tall is the barn? SOLUTION: Draw a rough figure for the given information. By the Geometric Mean (Altitude) Theorem the altitude drawn to the hypotenuse of a right triangle separates the hypotenuse into two segments. The length of this altitude is the geometric mean between the lengths of these two segments. The total height of the barn is 45 + 5 = 50 ft. ANSWER: 50 ft Find x. 16. SOLUTION: Use the Pythagorean theorem to find the hypotenuse of the right triangle. ANSWER: eSolutions Manual - Powered by Cognero Page 5 The total height of the barn is 45 + 5 = 50 ft. ANSWER: Study Guide and Review 50 ft Find x. 16. SOLUTION: Use the Pythagorean theorem to find the hypotenuse of the right triangle. ANSWER: 17. SOLUTION: Use the Pythagorean theorem to find the missing side of the right triangle. ANSWER: Determine whether each set of numbers can be the measures of the sides of a triangle. If so, classify the triangle as acute, obtuse, or right. Justify your answer. 18. 7, 24, 25 SOLUTION: By the Triangle Inequality Theorem, the sum of the lengths of any two sides should be greater than the length of the eSolutions Page 6 thirdManual side. - Powered by Cognero ANSWER: Study Guide and Review Determine whether each set of numbers can be the measures of the sides of a triangle. If so, classify the triangle as acute, obtuse, or right. Justify your answer. 18. 7, 24, 25 SOLUTION: By the Triangle Inequality Theorem, the sum of the lengths of any two sides should be greater than the length of the third side. Therefore, the set of numbers can be measures of a triangle. Classify the triangle by comparing the square of the longest side to the sum of the squares of the other two sides. Therefore, by the converse of Pythagorean Theorem, a triangle with the given measures will be a right triangle. ANSWER: Yes; right 19. 13, 15, 16 SOLUTION: By the Triangle Inequality Theorem, the sum of the lengths of any two sides should be greater than the length of the third side. Therefore, the set of numbers can be measures of a triangle. Now, classify the triangle by comparing the square of the longest side to the sum of the squares of the other two sides. Therefore, Pythagorean Inequality eSolutions Manual -by Powered by Cognero ANSWER: Yes; acute Theorem, a triangle with the given measures will be an acute triangle. Page 7 Yes; right Study Guide and Review 19. 13, 15, 16 SOLUTION: By the Triangle Inequality Theorem, the sum of the lengths of any two sides should be greater than the length of the third side. Therefore, the set of numbers can be measures of a triangle. Now, classify the triangle by comparing the square of the longest side to the sum of the squares of the other two sides. Therefore, by Pythagorean Inequality Theorem, a triangle with the given measures will be an acute triangle. ANSWER: Yes; acute 20. 65, 72, 88 SOLUTION: By the Triangle Inequality Theorem, the sum of the lengths of any two sides should be greater than the length of the third side. Therefore, the set of numbers can be measures of a triangle. Now, classify the triangle by comparing the square of the longest side to the sum of the squares of the other two sides. Therefore, by Pythagorean Inequality Theorem, a triangle with the given measures will be an acute triangle. ANSWER: eSolutions Manual - Powered by Cognero Yes; acute Page 8 ANSWER: Yes; acute Study Guide and Review 20. 65, 72, 88 SOLUTION: By the Triangle Inequality Theorem, the sum of the lengths of any two sides should be greater than the length of the third side. Therefore, the set of numbers can be measures of a triangle. Now, classify the triangle by comparing the square of the longest side to the sum of the squares of the other two sides. Therefore, by Pythagorean Inequality Theorem, a triangle with the given measures will be an acute triangle. ANSWER: Yes; acute 21. SWIMMING Alexi walks 27 meters south and 38 meters east to get around a lake. Her sister swims directly across the lake. How many meters to the nearest tenth did Alexi’s sister save by swimming? SOLUTION: Let x be the distance across the river. The distance saved would be the difference between the sum of the two legs of the triangle and the hypotenuse (distance across the river). distance saved = (27+38) – 46.6 = 18.4 Alexi’s sister saved about 18.4 meters by swimming across the river. eSolutions Manual - Powered by Cognero ANSWER: 18.4 m Page 9 Study Guide and Review 21. SWIMMING Alexi walks 27 meters south and 38 meters east to get around a lake. Her sister swims directly across the lake. How many meters to the nearest tenth did Alexi’s sister save by swimming? SOLUTION: Let x be the distance across the river. The distance saved would be the difference between the sum of the two legs of the triangle and the hypotenuse (distance across the river). distance saved = (27+38) – 46.6 = 18.4 Alexi’s sister saved about 18.4 meters by swimming across the river. ANSWER: 18.4 m Find x and y. 22. SOLUTION: In a 30°-60°-90° triangle, the length of the hypotenuse h is 2 times the length of the shorter leg s, and the length of the longer leg l is times the length of the shorter leg. Here, the length of the hypotenuse is Then, the shorter leg is x and the longer leg is 15. So, . Also we have, ANSWER: 23. eSolutions Manual - Powered by Cognero SOLUTION: The given triangle is an isosceles right triangle, that is, 45°-45°-90° triangle. So, Page 10 . Also we have, ANSWER: Study Guide and Review 23. SOLUTION: The given triangle is an isosceles right triangle, that is, 45°-45°-90° triangle. So, . In a 45°-45°-90° triangle, the legs l are congruent and the length of the hypotenuse h is Here, Solve for x. times the length of a leg. ANSWER: 24. CLIMBING Jason is adding a climbing wall to his little brother’s swing-set. If he starts building 5 feet out from the existing structure, and wants it to have a angle, how long should the wall be? SOLUTION: 10 ft. Since the ground and the side of the play structure make a angle, this is a is 5 feet. The climbing wall will be the hypotenuse, so it is 10 feet. - - triangle. The short side ANSWER: 10 ft. sample answer: since the ground and the side of the play structure make a angle, this is a triangle. The short side is 5 feet. The climbing wall will be the hypotenuse, so it is 10 feet. - - Express each ratio as a fraction and as a decimal to the nearest hundredth. eSolutions Manual - Powered by Cognero Page 11 is 5 feet. The climbing wall will be the hypotenuse, so it is 10 feet. ANSWER: 10Guide ft. sample angle, this is a Study andanswer: Reviewsince the ground and the side of the play structure make a triangle. The short side is 5 feet. The climbing wall will be the hypotenuse, so it is 10 feet. - - Express each ratio as a fraction and as a decimal to the nearest hundredth. 25. sin A SOLUTION: The sine of an angle is defined as the ratio of the opposite side to the hypotenuse. So, ANSWER: 26. tan B SOLUTION: The tangent of an angle is defined as the ratio of the opposite side to the adjacent side. So, ANSWER: 27. sin B SOLUTION: The sine of an angle is defined as the ratio of the opposite side to the hypotenuse. So, ANSWER: 28. cos A SOLUTION: The cosine of an angle is defined as the ratio of the adjacent side to the hypotenuse. So, ANSWER: 29. tan A SOLUTION: eSolutions Manual - Powered by Cognero The tangent of an angle is defined as the ratio of the opposite side to the adjacent side. So, Page 12 ANSWER: Study Guide and Review 29. tan A SOLUTION: The tangent of an angle is defined as the ratio of the opposite side to the adjacent side. So, ANSWER: 30. cos B SOLUTION: The cosine of an angle is defined as the ratio of the adjacent side to the hypotenuse. So, ANSWER: Find x. 31. SOLUTION: The tangent of an angle is defined as the ratio of the opposite side to the adjacent side. So, Solve for x: Use a calculator to find the value of x. Make sure your calculator is in degree mode. Manual - Powered by Cognero eSolutions ANSWER: Page 13 ANSWER: Study Guide and Review Find x. 31. SOLUTION: The tangent of an angle is defined as the ratio of the opposite side to the adjacent side. So, Solve for x: Use a calculator to find the value of x. Make sure your calculator is in degree mode. ANSWER: 32.2 32. SOLUTION: The sine of an angle is defined as the ratio of the opposite side to the hypotenuse. So, First, multiply both sides by x. eSolutions Manual - Powered by Cognero Divide both sides by sin 43°. Page 14 ANSWER: Study Guide and Review 32.2 32. SOLUTION: The sine of an angle is defined as the ratio of the opposite side to the hypotenuse. So, First, multiply both sides by x. Divide both sides by sin 43°. Use a calculator to find the value of x. Make sure your calculator is in degree mode. ANSWER: 38.1 33. GARDENING Sofia wants to put a flower bed in the corner of her yard by laying a stone border that starts 3 feet from the corner of one fence and ends 6 feet from the corner of the other fence. Find the angles, x and y, the fence make with the border. SOLUTION: eSolutions Manual - Powered by Cognero Page 15 ANSWER: Study Guide and Review 38.1 33. GARDENING Sofia wants to put a flower bed in the corner of her yard by laying a stone border that starts 3 feet from the corner of one fence and ends 6 feet from the corner of the other fence. Find the angles, x and y, the fence make with the border. SOLUTION: Use tangent. y = 90 – 63.4 or 26.6 ANSWER: and 34. JOBS Tom delivers papers on a rural route from his car. If he throws a paper from a height of 4 feet, and it lands 15 feet from the car, at what angle of depression did he throw the paper to the nearest degree? SOLUTION: Let x be the unknown. eSolutions Manual - Powered by Cognero Page 16 y = 90 – 63.4 or 26.6 ANSWER: Study Guide and Review and 34. JOBS Tom delivers papers on a rural route from his car. If he throws a paper from a height of 4 feet, and it lands 15 feet from the car, at what angle of depression did he throw the paper to the nearest degree? SOLUTION: Let x be the unknown. ANSWER: 35. TOWER There is a cell phone tower in the field across from Jen’s house. If Jen walks 50 feet from the tower, and finds the angle of elevation from her position to the top of the tower to be , how tall is the tower? SOLUTION: Let x be the height of the tower. So, the height of the tower is 86.6 feet. ANSWER: 86.6 ft FindManual x. Round angle measures eSolutions - Powered by Cognero to the nearest degree and side measures to the nearest tenth. Page 17 So, the height of the tower is 86.6 feet. ANSWER: Study Guide and Review 86.6 ft Find x. Round angle measures to the nearest degree and side measures to the nearest tenth. 36. SOLUTION: Since we are given one side and two angles, we can set up a proportion using the Law of Sines. The angle opposite the side of length 73 has a degree measure of 180° – 33° – 86° = 61°. ANSWER: 15.0 37. SOLUTION: We are given the measures of two sides and their included angle, so use the Law of Cosines. ANSWER: 15.2 eSolutions Manual - Powered by Cognero Page 18 38. SKIING At Crazy Ed’s Ski resort, Ed wants to put in another ski lift for the skiers to ride from the base to the summit of the mountain. The run over which the ski lift will go is represented by the figure below. The length of the ANSWER: Study Guide and Review 15.0 37. SOLUTION: We are given the measures of two sides and their included angle, so use the Law of Cosines. ANSWER: 15.2 38. SKIING At Crazy Ed’s Ski resort, Ed wants to put in another ski lift for the skiers to ride from the base to the summit of the mountain. The run over which the ski lift will go is represented by the figure below. The length of the lift is represented by SB. If Ed needs twice as much cable as the length of , how much cable does he need? SOLUTION: We are given the measures of two sides and their included angle, so use the Law of Cosines. Ed needs 2(1800.83) or about 3601.7 feet cable. ANSWER: 3601.7 ft eSolutions Manual - Powered by Cognero 39. Write the component form of the vector shown. Page 19 ANSWER: Study Guide and Review 15.2 38. SKIING At Crazy Ed’s Ski resort, Ed wants to put in another ski lift for the skiers to ride from the base to the summit of the mountain. The run over which the ski lift will go is represented by the figure below. The length of the lift is represented by SB. If Ed needs twice as much cable as the length of , how much cable does he need? SOLUTION: We are given the measures of two sides and their included angle, so use the Law of Cosines. Ed needs 2(1800.83) or about 3601.7 feet cable. ANSWER: 3601.7 ft 39. Write the component form of the vector shown. SOLUTION: Use component notation and find the change in x-values and the change in y-values. The coordinates of A and B are (5, 2) and (–1, –3) respectively. ANSWER: 40. Copy the vectors to find eSolutions Manual - Powered by Cognero . Page 20 ANSWER: Study Guide and Review 40. Copy the vectors to find . SOLUTION: Using the Parallelogram method, start by translating until its initial point touches the initial point of . Next, complete the parallelogram, as shown: Draw in the diagonal, which represents the resulting vector when adding and . ANSWER: 41. Given that is and is , find the component form of . SOLUTION: ANSWER: eSolutions Manual - Powered by Cognero Page 21